In the past, organizational computing has been provided in a main frame environment wherein security was implicitly enforced. All users shared a central resource. Access to the central resource was typically by a password and threats to security were posed mainly by password compromise. Solutions to such security problems typically included periodic password changes, audit trails and access restrictions based on user identity.
Open network systems have become prevalent and have been replacing main frames. However, with such a replacement, computing resources have become vulnerable to a myriad of new assaults. For example, the broadcast nature of the ETHERNET.TM. protocol makes it particularly susceptible to attack, since any attached device has the potential to examine all network traffic.
Solutions have been advanced with regard to such data transmission security. U.S. Pat. No. 4,901,348 to Nichols et al, discloses an arrangement for securing data transmission to and from one data device from among a plurality of data devices sharing a common interface. The patent discloses a master communication bus connected to a plurality of data transmitting and receiving devices via a single interface. Circuitry is provided in the common interface which generates a jamming signal to all devices connected to the interface except for that one device which is either transmitting or receiving a data-transmission. This jamming signal inhibits all the connected devices for monitoring and detecting the data transmission process of the interface. In this way, the one transmitting and receiving device is enabled to either transmit or receive data during the generation of the jamming signal which ensures a secure data transmission and prevents eaves dropping by the other devices. This jamming signal is then removed at the conclusion of the data transmission to or from the device.
Such an arrangement which relies on a jamming signal has significant drawbacks and limitations. Such system which rely on jamming signals do not address problems with regard to the security or backbone links. Further, such system only are useful for multi-drop bus topology and are not effective for ring topologies.